Solar panel cost in Sevenoaks (TN14)

See realistic solar installation costs, savings and payback for TN14 (Sevenoaks) in under a minute using official UK data. Start with the calculator, then get a no-obligation quote from an MCS-certified installer. You can also ask the SolarByPostcode assistant to sanity-check your roof, bills and plans.

Solar Calculator

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System Size

Roof Direction

Battery Storage

Export Value

Your Numbers

Break-even
9.5 years
After this, it's pure profit
Upfront Cost
£9,767
What you pay to get started
Annual Benefit
£1,023
What you save every year
Profit Over 25 Years
£15,821
After paying itself off, you're this much ahead

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How we calculate this

Solar generation: Based on typical south-facing roof at 35° angle. We account for weather, dirt, and system losses (14%).

How much you'll use directly:

  • Without battery: You'll use about 40% of what you generate. The rest gets sold back to the grid.
  • With 5 kWh battery: You'll use about 70% (battery stores extra for evening use).
  • With 10 kWh battery: You'll use about 75% (more storage means less exported).
  • Panel-only payback: The official cost per kW is lower above 4 kW, so a 5–6 kW system can pay back a little faster than a 3–4 kW system on otherwise identical assumptions.
  • Battery & payback: Batteries raise self-use and cut bills, but added hardware cost often lengthens break-even at typical UK rates.
  • When a battery can still make sense:
    • Evening-heavy usage patterns
    • Time-of-use tariffs / cheap night rates
    • Low export rate vs. high unit rate
    • Heat pump or EV charging synergy
    • Optional backup/resilience (system-dependent)
    • Lower evening-hour CO₂ vs. grid

Panel costs: Uses March 2026 TIC mean installation costs: £1,827/kW up to 4 kW and £1,628/kW above 4 kW.

Other costs: Battery prices are modelled at £700 per kWh. Export tariffs vary by supplier (usually 5–15p per kWh).

Grid connection: Systems up to about 3.7 kW typically need just a notification (G98). Larger systems may need permission (G99).

These are typical values based on average usage patterns. Your actual results will vary based on your roof, shading, and how you use electricity.

Your area in context

Read the full story

A typical roof here lands around 6.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 1023 kWh per year on a south-facing roof. We value self-used electricity at 26.7p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
26.7p/kWh
Standing charge
54.5p/day
Sunshine yield (south)
1023 kWh/kW
Export price (baseline)
10p/kWh

Browse the scenarios below. Each battery size has its own expand — open the one that matches your plan (or just explore). For each system size (2–8 kW) we show annual output, how much you use directly, what gets exported, annual benefit, upfront cost, break-even, and a 20-year net. Negative numbers are possible — that’s the honest trade-off when adding more battery than your usage profile justifies.

No battery 5 kW example → Annual benefit: £853, Upfront: £8,139, Break-even: 9.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2047 kWh 819 kWh 1228 kWh £218 £123 £341 £3,256 9.5 yrs £3,568
3 kW 3070 kWh 1228 kWh 1842 kWh £328 £184 £512 £4,883 9.5 yrs £5,352
4 kW 4094 kWh 1637 kWh 2456 kWh £437 £246 £682 £6,511 9.5 yrs £7,136
5 kW 5117 kWh 2047 kWh 3070 kWh £546 £307 £853 £8,139 9.5 yrs £8,919
6 kW 6140 kWh 2456 kWh 3684 kWh £655 £368 £1,023 £9,767 9.5 yrs £10,703
7 kW 7164 kWh 2866 kWh 4298 kWh £764 £430 £1,194 £11,394 9.5 yrs £12,487
8 kW 8187 kWh 3275 kWh 4912 kWh £873 £491 £1,365 £13,022 9.5 yrs £14,271

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £1,024, Upfront: £10,239, Break-even: 10.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2047 kWh 1228 kWh 819 kWh £328 £82 £409 £5,356 13.1 yrs £2,833
3 kW 3070 kWh 1842 kWh 1228 kWh £491 £123 £614 £6,983 11.4 yrs £5,299
4 kW 4094 kWh 2456 kWh 1637 kWh £655 £164 £819 £8,611 10.5 yrs £7,765
5 kW 5117 kWh 3070 kWh 2047 kWh £819 £205 £1,024 £10,239 10.0 yrs £10,231
6 kW 6140 kWh 3684 kWh 2456 kWh £983 £246 £1,228 £11,867 9.7 yrs £12,698
7 kW 7164 kWh 4298 kWh 2866 kWh £1,146 £287 £1,433 £13,494 9.4 yrs £15,164
8 kW 8187 kWh 4912 kWh 3275 kWh £1,310 £327 £1,638 £15,122 9.2 yrs £17,630

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £1,109, Upfront: £11,639, Break-even: 10.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2047 kWh 1433 kWh 614 kWh £382 £61 £444 £6,756 15.2 yrs £2,115
3 kW 3070 kWh 2149 kWh 921 kWh £573 £92 £665 £8,383 12.6 yrs £4,922
4 kW 4094 kWh 2866 kWh 1228 kWh £764 £123 £887 £10,011 11.3 yrs £7,730
5 kW 5117 kWh 3582 kWh 1535 kWh £955 £154 £1,109 £11,639 10.5 yrs £10,537
6 kW 6140 kWh 4298 kWh 1842 kWh £1,146 £184 £1,331 £13,267 10.0 yrs £13,345
7 kW 7164 kWh 5015 kWh 2149 kWh £1,337 £215 £1,552 £14,894 9.6 yrs £16,152
8 kW 8187 kWh 5731 kWh 2456 kWh £1,528 £246 £1,774 £16,522 9.3 yrs £18,960

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £1,134, Upfront: £13,389, Break-even: 11.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2047 kWh 1494 kWh 553 kWh £398 £55 £454 £8,506 18.7 yrs £570
3 kW 3070 kWh 2241 kWh 829 kWh £598 £83 £681 £10,133 14.9 yrs £3,480
4 kW 4094 kWh 2988 kWh 1105 kWh £797 £111 £908 £11,761 13.0 yrs £6,389
5 kW 5117 kWh 3735 kWh 1382 kWh £996 £138 £1,134 £13,389 11.8 yrs £9,299
6 kW 6140 kWh 4483 kWh 1658 kWh £1,195 £166 £1,361 £15,017 11.0 yrs £12,209
7 kW 7164 kWh 5230 kWh 1934 kWh £1,395 £193 £1,588 £16,644 10.5 yrs £15,119
8 kW 8187 kWh 5977 kWh 2211 kWh £1,594 £221 £1,815 £18,272 10.1 yrs £18,029

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £1,151, Upfront: £15,139, Break-even: 13.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2047 kWh 1535 kWh 512 kWh £409 £51 £461 £10,256 22.3 yrs £-1,044
3 kW 3070 kWh 2303 kWh 768 kWh £614 £77 £691 £11,883 17.2 yrs £1,934
4 kW 4094 kWh 3070 kWh 1023 kWh £819 £102 £921 £13,511 14.7 yrs £4,912
5 kW 5117 kWh 3838 kWh 1279 kWh £1,024 £128 £1,151 £15,139 13.1 yrs £7,890
6 kW 6140 kWh 4605 kWh 1535 kWh £1,228 £154 £1,382 £16,767 12.1 yrs £10,869
7 kW 7164 kWh 5373 kWh 1791 kWh £1,433 £179 £1,612 £18,394 11.4 yrs £13,847
8 kW 8187 kWh 6140 kWh 2047 kWh £1,638 £205 £1,842 £20,022 10.9 yrs £16,825

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £1,169, Upfront: £17,589, Break-even: 15.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2047 kWh 1576 kWh 471 kWh £420 £47 £467 £12,706 27.2 yrs £-3,357
3 kW 3070 kWh 2364 kWh 706 kWh £630 £71 £701 £14,333 20.4 yrs £-311
4 kW 4094 kWh 3152 kWh 942 kWh £841 £94 £935 £15,961 17.1 yrs £2,735
5 kW 5117 kWh 3940 kWh 1177 kWh £1,051 £118 £1,169 £17,589 15.1 yrs £5,782
6 kW 6140 kWh 4728 kWh 1412 kWh £1,261 £141 £1,402 £19,217 13.7 yrs £8,828
7 kW 7164 kWh 5516 kWh 1648 kWh £1,471 £165 £1,636 £20,844 12.7 yrs £11,874
8 kW 8187 kWh 6304 kWh 1883 kWh £1,681 £188 £1,870 £22,472 12.0 yrs £14,921

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

Figures are illustrative and use the same method as the calculator above. For exact results, adjust your roof direction, tariff, and usage in the calculator.

Before you request quotes in Sevenoaks

Use the numbers above to sanity-check installer quotes. The main things to compare are system size, battery assumptions, payback claims, MCS certification, DNO paperwork and export assumptions.

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Seasonal solar output in TN14

Monthly generation per kilowatt of solar panels

kWh 39 Jan 52 Feb 85 Mar 114 Apr 123 May 125 Jun 125 Jul 113 Aug 96 Sep 68 Oct 48 Nov 35 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 49.2% of an average month (Dec–Feb)

Best / worst month: Jul / Dec

These figures show output per kilowatt (kW) of panels installed. In winter, a 1 kW system here produces about 42 kWh per month; the average month produces around 85 kWh. So a typical 4 kW home system would generate roughly 168 kWh in winter, or 341 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.67p/kWh
Daily Fixed Charge
54.45p/day
Local Sunshine
1023kWh/kW
A 1 kW system generates ~1023 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
6.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 70% • Flats: 18% • Bungalows: 10% Based on 3,883 properties

Coverage

Sevenoaks (96%)|Bromley (4%)

Areas Covered

Otford and Shoreham, Halstead, Knockholt and Badgers Mount, Brasted, Chevening and Sundridge, Sevenoaks Town and St John's, Sevenoaks Northern, Seal and Weald + 6 more

Data Sources & Assumptions

Solar yield: PVGIS (EU Joint Research Centre), January 2025 data

Electricity rates: Ofgem price cap, Q3 2026

Installation costs: DESNZ/MCS data, March 2026 (TIC)

Property data: EPC open data (Open Government Licence), aggregated

All estimates are typical values. Actual results vary based on your specific situation, roof characteristics, and usage patterns.